An important component of mobile computing devices is the battery. Typically Lithium-ion batteries are used in such applications. Batteries using such technologies typically last between two and three years during which they continually lose capacity to hold a charge for long enough periods of time. The capacity loss manifests itself in increased internal resistance caused by oxidation. Eventually, the cell resistance reaches a point where the battery pack can no longer deliver the stored energy although the battery may still show as being fully charged. Increasing internal resistance with cycle life and age is typical for cobalt-based lithium-ion, a system that is used for cell phones, cameras and laptops because of high energy density. The speed by which lithium-ion ages is governed by temperature and state-of-charge.
Most mobile devices allow the battery to be fully-charged while the device is plugged into fixed power from an AC-DC adapter. Using a fully-charged battery while plugged into main power, as well as the elevated temperatures while the device is in operation contribute to a reduction in the life span of a battery. An ideal way to prolong battery life would be to disconnect the battery from the device being supplied while the device is drawing power from an AC-DC adapter. However, most users are unwilling to do so because of fear of loss of data if the operation of the AC-DC adapter is interrupted in any way.
Thus, there is a need for an improved system for providing a battery charging process for rechargeable batteries in order to increase battery life span.